1. Field of the Invention
The present invention relates to an inkjet printer for ejecting ink from nozzles of a recording head onto a printing medium so as to form an image.
2. Description of the Related Art
In the related art, inkjet printers that execute printing by ejecting very small ink droplets from a plurality of nozzles provided in a recording head are classified into so-called serial head type printers and so-called line head type printers. Each of the serial head type printers executes printing by the combination of a main-scanning-direction moving operation for ejecting ink while moving a recording head in a main scanning direction (paper width direction) and a sub-scanning-direction moving operation for moving paper in a sub-scanning direction. On the other hand, each of the line head type printers includes a line head having a printable width corresponding to the paper width of paper as a printing medium. In the line head type printer, printing is performed while moving the line head and the paper relatively to each other. Particularly in the line head type printer, it is unnecessary to move the recording head in the main scanning direction of the paper. Thus, the print speed can be increased in comparison with that in the serial head type printer.
In each of the serial head type printer and the line head type printer in the related art, ink ejection from minute nozzles provided in the recording head must be kept good in order to obtain a high quality image. Therefore, in inkjet printers, so-called capping, purging and flushing are performed. Capping is an operation of sealing ink ejection ports (nozzle outlets) of the recording head with a cap. Purging is an operation of sucking ink in the nozzles from the ejection port side or discharging compressed ink forcibly from the ink ejection ports to thereby eject the ink from nozzles. Flushing is an operation of ejecting a small amount of ink at the time of printing. Capping can prevent the viscosity of ink in the nozzles from increasing, and prevent foreign matters or the like from being mixed into the ink.
JP-A-2001-293874 (pages 5 to 6; and FIG. 8) discloses an inkjet printer including a movable shutter having a cap. According to the technique disclosed in JP-A-2001-293874, the shutter is moved to cap ink ejection ports when a recording head is not in use.